<?php

    class encoder {
        public static function to_utf8 ($output) {
            return preg_replace_callback('/\\\\u([0-9a-f]{4})/i', 'encoder::replace_unicode_escape_sequence', $output);
        }
        
        private static function replace_unicode_escape_sequence($match) { 
            return mb_convert_encoding(pack('H*', $match[1]), 'UTF-8', 'UCS-2BE');
        }
    }
?>
